ONTARIO GAS TECHNICIAN 1 (G1)
CERTIFICATION EXAM
230 Practice MCQs with Answers & Rationales
SECTION 1: ONTARIO TECHNICAL STANDARDS &
SAFETY AUTHORITY (TSSA) & REGULATIONS
1. Which organization is responsible for administering the Gas Technician certification program
in Ontario?
A) Ontario Ministry of Labour B) Technical Standards and Safety Authority (TSSA) C) Ontario
College of Trades (OCOT) D) Natural Resources Canada
(Correct answer: B) Rationale: The Technical Standards and Safety Authority (TSSA) is the
Ontario authority responsible for administering the Gas Technician certification program, issuing
certificates of qualification, and enforcing the Technical Standards and Safety Act, 2000 and the
Gas Distribution Act. TSSA regulates gas fitting work to ensure public safety.
2. The primary legislation governing gas fitting work in Ontario is:
A) The Ontario Building Code Act B) The Technical Standards and Safety Act, 2000 (TSSA
Act) and associated regulations C) The Occupational Health and Safety Act (OHSA) D) The
Ontario Fire Code
(Correct answer: B) Rationale: The Technical Standards and Safety Act, 2000, along with
Ontario Regulation 212/01 (Gas Pipeline Systems) and Ontario Regulation 215/01 (Propane
Storage and Handling), forms the primary legislative framework governing gas fitting activities
in Ontario. TSSA administers and enforces these regulations.
3. A Gas Technician 1 (G1) certificate of qualification in Ontario authorizes the holder to:
A) Install only residential gas appliances B) Install, service, and repair all gas systems including
high-pressure transmission pipelines C) Perform all gas fitting work covered by G2, plus high-
pressure systems, gas pressure regulating stations, and complex industrial gas systems D) Work
only on commercial gas systems
,(Correct answer: C) Rationale: A G1 certificate of qualification is the highest level of gas
technician certification in Ontario. It encompasses all G2 scope of work plus authorization to
work on high-pressure gas distribution systems, gas pressure regulating stations, gas
measurement systems, and complex industrial/commercial gas systems beyond G2 scope.
4. Ontario Regulation 212/01 (Gas Pipeline Systems) applies to:
A) Only propane distribution systems B) Natural gas and propane piping systems operating
below 700 kPa C) Natural gas distribution systems, including storage facilities, transmission
lines, and associated equipment D) Only consumer gas installations within buildings
(Correct answer: C) Rationale: Ontario Regulation 212/01 (Gas Pipeline Systems) governs the
design, construction, installation, operation, maintenance, and abandonment of natural gas
pipeline systems in Ontario, including distribution mains, service pipes, pressure regulating
stations, and associated facilities.
5. What is the maximum operating pressure for systems covered under the G2 scope of work in
Ontario?
A) 35 kPa B) 200 kPa C) 700 kPa D) 2,000 kPa
(Correct answer: C) Rationale: The G2 scope of work covers gas fitting on systems operating
at pressures up to 700 kPa gauge. Systems operating above 700 kPa require a G1 certificate of
qualification, reflecting the additional training and competency required to work safely on
higher-pressure gas systems.
6. Which CSA standard is the primary reference for natural gas and propane installation in
buildings in Ontario?
A) CSA B149.1 B) CSA B149.2 C) CSA Z21.13 D) CSA B51
(Correct answer: A) Rationale: CSA B149.1 (Natural Gas and Propane Installation Code) is
the primary code governing the installation of natural gas and propane systems in buildings in
Canada, including Ontario. It is adopted by reference in Ontario's regulations and sets the
standards for gas piping, appliance connections, venting, and related installations.
7. CSA B149.2 applies to:
,A) Natural gas installation in commercial buildings B) Propane storage and handling at
consumer and commercial sites C) Gas pressure regulating equipment D) Gas measurement
systems
(Correct answer: B) Rationale: CSA B149.2 (Propane Storage and Handling Code) governs
propane storage, handling, and distribution systems including LP-Gas containers, piping,
vaporizers, and associated equipment at consumer sites, commercial facilities, and distribution
points.
8. In Ontario, a gas fitting permit is required for:
A) Only new construction gas installations B) All gas fitting work including new installations,
alterations, extensions, and replacement of gas appliances C) Only work on high-pressure
systems D) Only commercial and industrial gas installations
(Correct answer: B) Rationale: Under Ontario's gas regulations, a permit is required for all
prescribed gas fitting work — including new installations, alterations, extensions to existing
systems, and replacement of gas appliances. The permit system ensures all work is inspected and
documented, maintaining the safety and integrity of gas systems.
9. A gas technician in Ontario must be registered with TSSA as an employee of a registered gas
contractor. The purpose of this requirement is:
A) To collect fees for TSSA operations B) To ensure that all gas fitting work is performed by
qualified individuals working for accountable contractors who are registered with and regulated
by TSSA C) To limit competition in the gas fitting industry D) To ensure all gas technicians
have liability insurance
(Correct answer: B) Rationale: The TSSA registration system creates accountability at both the
individual technician and contractor levels. Registered contractors are responsible for the work
performed by their employees and must ensure only certified technicians perform gas fitting
work within their scope. This dual-layer accountability protects public safety.
10. Under Ontario gas regulations, what must a gas technician do upon discovering a gas leak in
an existing installation?
A) Continue the scheduled work and note the leak for future repair B) Immediately shut off the
gas supply if possible, evacuate the area, ventilate, and notify TSSA and the gas utility — do not
restore service until the leak is repaired and the installation is safe C) Repair the leak without
, filing a report if the repair is minor D) Notify only the property owner and allow them to decide
on the next steps
(Correct answer: B) Rationale: Upon discovering a gas leak, safety is the absolute priority. The
technician must immediately shut off supply if safely possible, evacuate and ventilate, contact
the gas utility and emergency services as needed, and notify TSSA of any reportable incident. No
work may continue and gas service cannot be restored until the leak is repaired and the system
verified safe.
SECTION 2: GAS PROPERTIES & COMBUSTION
11. What is the primary component of natural gas?
A) Propane (C3H8) B) Methane (CH4) C) Butane (C4H10) D) Ethane (C2H6)
(Correct answer: B) Rationale: Natural gas is predominantly methane (CH4), typically
comprising 85–98% of the mixture. It also contains smaller amounts of ethane, propane, butane,
and trace amounts of other gases. Understanding the composition of natural gas is fundamental
to gas fitting work, as it affects combustion characteristics, heating value, and system design.
12. The specific gravity of natural gas relative to air is approximately:
A) 1.52 (heavier than air) B) 0.60 (lighter than air) C) 1.00 (same as air) D) 2.01 (heavier than
air)
(Correct answer: B) Rationale: Natural gas (primarily methane) has a specific gravity of
approximately 0.55–0.65 relative to air (air = 1.0), making it lighter than air. This is a critical
safety characteristic — natural gas rises and dissipates if released in a ventilated area. This
affects leak detection procedures (check high areas) and venting requirements.
13. The specific gravity of propane relative to air is approximately:
A) 0.60 (lighter than air) B) 1.00 (same as air) C) 1.52 (heavier than air) D) 2.50 (heavier than
air)
(Correct answer: C) Rationale: Propane (C3H8) has a specific gravity of approximately 1.52
relative to air, making it significantly heavier than air. This is a critical safety distinction from
natural gas — propane will settle in low areas (basements, crawl spaces, trenches) where it can
accumulate to explosive concentrations. This affects leak detection (check low areas), equipment
placement, and emergency procedures.
CERTIFICATION EXAM
230 Practice MCQs with Answers & Rationales
SECTION 1: ONTARIO TECHNICAL STANDARDS &
SAFETY AUTHORITY (TSSA) & REGULATIONS
1. Which organization is responsible for administering the Gas Technician certification program
in Ontario?
A) Ontario Ministry of Labour B) Technical Standards and Safety Authority (TSSA) C) Ontario
College of Trades (OCOT) D) Natural Resources Canada
(Correct answer: B) Rationale: The Technical Standards and Safety Authority (TSSA) is the
Ontario authority responsible for administering the Gas Technician certification program, issuing
certificates of qualification, and enforcing the Technical Standards and Safety Act, 2000 and the
Gas Distribution Act. TSSA regulates gas fitting work to ensure public safety.
2. The primary legislation governing gas fitting work in Ontario is:
A) The Ontario Building Code Act B) The Technical Standards and Safety Act, 2000 (TSSA
Act) and associated regulations C) The Occupational Health and Safety Act (OHSA) D) The
Ontario Fire Code
(Correct answer: B) Rationale: The Technical Standards and Safety Act, 2000, along with
Ontario Regulation 212/01 (Gas Pipeline Systems) and Ontario Regulation 215/01 (Propane
Storage and Handling), forms the primary legislative framework governing gas fitting activities
in Ontario. TSSA administers and enforces these regulations.
3. A Gas Technician 1 (G1) certificate of qualification in Ontario authorizes the holder to:
A) Install only residential gas appliances B) Install, service, and repair all gas systems including
high-pressure transmission pipelines C) Perform all gas fitting work covered by G2, plus high-
pressure systems, gas pressure regulating stations, and complex industrial gas systems D) Work
only on commercial gas systems
,(Correct answer: C) Rationale: A G1 certificate of qualification is the highest level of gas
technician certification in Ontario. It encompasses all G2 scope of work plus authorization to
work on high-pressure gas distribution systems, gas pressure regulating stations, gas
measurement systems, and complex industrial/commercial gas systems beyond G2 scope.
4. Ontario Regulation 212/01 (Gas Pipeline Systems) applies to:
A) Only propane distribution systems B) Natural gas and propane piping systems operating
below 700 kPa C) Natural gas distribution systems, including storage facilities, transmission
lines, and associated equipment D) Only consumer gas installations within buildings
(Correct answer: C) Rationale: Ontario Regulation 212/01 (Gas Pipeline Systems) governs the
design, construction, installation, operation, maintenance, and abandonment of natural gas
pipeline systems in Ontario, including distribution mains, service pipes, pressure regulating
stations, and associated facilities.
5. What is the maximum operating pressure for systems covered under the G2 scope of work in
Ontario?
A) 35 kPa B) 200 kPa C) 700 kPa D) 2,000 kPa
(Correct answer: C) Rationale: The G2 scope of work covers gas fitting on systems operating
at pressures up to 700 kPa gauge. Systems operating above 700 kPa require a G1 certificate of
qualification, reflecting the additional training and competency required to work safely on
higher-pressure gas systems.
6. Which CSA standard is the primary reference for natural gas and propane installation in
buildings in Ontario?
A) CSA B149.1 B) CSA B149.2 C) CSA Z21.13 D) CSA B51
(Correct answer: A) Rationale: CSA B149.1 (Natural Gas and Propane Installation Code) is
the primary code governing the installation of natural gas and propane systems in buildings in
Canada, including Ontario. It is adopted by reference in Ontario's regulations and sets the
standards for gas piping, appliance connections, venting, and related installations.
7. CSA B149.2 applies to:
,A) Natural gas installation in commercial buildings B) Propane storage and handling at
consumer and commercial sites C) Gas pressure regulating equipment D) Gas measurement
systems
(Correct answer: B) Rationale: CSA B149.2 (Propane Storage and Handling Code) governs
propane storage, handling, and distribution systems including LP-Gas containers, piping,
vaporizers, and associated equipment at consumer sites, commercial facilities, and distribution
points.
8. In Ontario, a gas fitting permit is required for:
A) Only new construction gas installations B) All gas fitting work including new installations,
alterations, extensions, and replacement of gas appliances C) Only work on high-pressure
systems D) Only commercial and industrial gas installations
(Correct answer: B) Rationale: Under Ontario's gas regulations, a permit is required for all
prescribed gas fitting work — including new installations, alterations, extensions to existing
systems, and replacement of gas appliances. The permit system ensures all work is inspected and
documented, maintaining the safety and integrity of gas systems.
9. A gas technician in Ontario must be registered with TSSA as an employee of a registered gas
contractor. The purpose of this requirement is:
A) To collect fees for TSSA operations B) To ensure that all gas fitting work is performed by
qualified individuals working for accountable contractors who are registered with and regulated
by TSSA C) To limit competition in the gas fitting industry D) To ensure all gas technicians
have liability insurance
(Correct answer: B) Rationale: The TSSA registration system creates accountability at both the
individual technician and contractor levels. Registered contractors are responsible for the work
performed by their employees and must ensure only certified technicians perform gas fitting
work within their scope. This dual-layer accountability protects public safety.
10. Under Ontario gas regulations, what must a gas technician do upon discovering a gas leak in
an existing installation?
A) Continue the scheduled work and note the leak for future repair B) Immediately shut off the
gas supply if possible, evacuate the area, ventilate, and notify TSSA and the gas utility — do not
restore service until the leak is repaired and the installation is safe C) Repair the leak without
, filing a report if the repair is minor D) Notify only the property owner and allow them to decide
on the next steps
(Correct answer: B) Rationale: Upon discovering a gas leak, safety is the absolute priority. The
technician must immediately shut off supply if safely possible, evacuate and ventilate, contact
the gas utility and emergency services as needed, and notify TSSA of any reportable incident. No
work may continue and gas service cannot be restored until the leak is repaired and the system
verified safe.
SECTION 2: GAS PROPERTIES & COMBUSTION
11. What is the primary component of natural gas?
A) Propane (C3H8) B) Methane (CH4) C) Butane (C4H10) D) Ethane (C2H6)
(Correct answer: B) Rationale: Natural gas is predominantly methane (CH4), typically
comprising 85–98% of the mixture. It also contains smaller amounts of ethane, propane, butane,
and trace amounts of other gases. Understanding the composition of natural gas is fundamental
to gas fitting work, as it affects combustion characteristics, heating value, and system design.
12. The specific gravity of natural gas relative to air is approximately:
A) 1.52 (heavier than air) B) 0.60 (lighter than air) C) 1.00 (same as air) D) 2.01 (heavier than
air)
(Correct answer: B) Rationale: Natural gas (primarily methane) has a specific gravity of
approximately 0.55–0.65 relative to air (air = 1.0), making it lighter than air. This is a critical
safety characteristic — natural gas rises and dissipates if released in a ventilated area. This
affects leak detection procedures (check high areas) and venting requirements.
13. The specific gravity of propane relative to air is approximately:
A) 0.60 (lighter than air) B) 1.00 (same as air) C) 1.52 (heavier than air) D) 2.50 (heavier than
air)
(Correct answer: C) Rationale: Propane (C3H8) has a specific gravity of approximately 1.52
relative to air, making it significantly heavier than air. This is a critical safety distinction from
natural gas — propane will settle in low areas (basements, crawl spaces, trenches) where it can
accumulate to explosive concentrations. This affects leak detection (check low areas), equipment
placement, and emergency procedures.
